Yes, I have tried it and yes it does work. I consider it very slightly less safe than a single tank with a single regulator and two second stages.
Back 30 years ago, there were no "tech" manifolds. We tried a lot of things back then. About the only one that was as safe as a modern manifold was connecting two tanks together below the valves with 5000psi seamless stainless steel tubing and fittings.
